Printed circuit edge connector



Aug. 1968 H. P. .1. GILISSEN 3,397,381

PRINTED CIRCUIT EDGE CONNECTOR Filed June 30, 1966 2 Sheets-Sheet 1 ug 13, 1968 H. P. J. GILISSEN 3 I 3,397,381

PRINTED CIRCUIT EDGE CONNECTOR Filed June 250, 1966 2 Sheets-Sheet 2 IOO ll zle United States Patent 3,397,381 PRINTED CIRCUIT EDGE CGNNECTOR Hermanus Petrus Johannes Gilissen, Vlijmen, North Brabant, Netherlands, assignor to AMP Incorporated, Harrisburg, Pa.

Filed June 30, 1966, Ser. No. 561,942 Claims priority, application Netherlands, July 5, 1965, 6508627 6 Claims. (Cl. 339176) ABSTRACT OF THE DISCLOSURE An electrical connector comprises a dielectric housing having a channel and -a pocket in communication with the channel so that a spring contact section of an electrical contact in the pocket extends within the channel and the electrical contact has a leg portion provided with a bowed area that resiliently and slidably engages a wall of the pocket to permit the spring contact section to remain substantially constant and to be substantially independent from the deflection of a bight of the spring contact sec tion while the spring contact section is under electricalengaging tension.

This invention relates to electrical connectors, and in particular to a printed circuit edge connector with constant contact pressure.

Electrical connector assemblies for connecting electrical leads to printed conductors on printed circuit panels are known, which comprise an insulating housing defining a channel for receiving an edge of the printed circuit panel, a pocket defined by the housing and communicating with the channel, and an electrical contact element in the pocket. The contact element has a contact spring portion formed as a loop, the bight of which is directed outwardly of the channel, one side of the loop engaging one Wall of the pocket adjacent the channel and having a contact portion protruding into the channel for making electrical contact with the printed conductor when the panel is inserted into the channel. The contact element normally has a connecting portion for connection to the lead. At its end remote from the bight, the other side of the loop is rigidly connected to the housing to act as a cantilever providing the contact pressure exerted by the contact portion against the printed conductor. The contact pressure thus varies continuously according to the relative positions of the printed conductor and the contact spring portion. When the panel is fully inserted in the channel, the contact pressure is therefore subject to variation as a result of irregularities in the thickness of the panel or panel vibration.

In an electrical connector assembly for connecting an electrical lead to a printed conductor on a printed circuit panel, the assembly comprises an insulating housing defining a channel for receiving an edge of the printed circuit panel, a pocket defined by the housing and communicating with the channel, and an electrical contact element in the pocket, the contact element having a contact spring portion formed as a loop, the bight of which is directed outwardly of the channel, one side of the loop engaging one wall of the pocket adjacent the channel and having a contact portion protruding into the channel for making electrical contact with the printed conductor when the panel is inserted into the channel, the contact element having a connecting portion for connection to the lead, the other side of the loop has according to the invention a bowed portion resiliently engaging the opposite wall of the pocket and terminating in a free end on the side of the bowed portion remote from the bight of the loop, the loop being spring loaded between the one wall of the pocket and the opposite wall of the pocket. Upon initial deflection of the loop as a result of a short initial inser- 3,397,381 Patented Aug. 13, 1968 tion of the panel, the loop is spring loaded between the panel and the opposite wall of the pocket instead of between the one wall and the opposite wall whereby the bowed portion slides relative to the opposite Wall upon further insertion of the panel into the channel so that the contact pressure exerted by the contact portion against the printed conductor remains substantially constant and is thus substantially independent of the extent to which the loop is finally deflected. The contact pressure is accordingly substantially uninfluenced by irregularities in the thickness of the panel or panel vibration.

Consequently, it is an object of this invention to pro vide a printed circuit edge connector which permits the insertion of a printed circuit panel into the channel so that the contact pressure exerted by the contact portion against the printed conductor remains constant.

Another object is to provide a printed circuit connector in which the contact pressure is substantially uninfluenced by irregularities in the printed circuit panel thickness.

Still another object is to provide a printed circuit connector which is substantially uninfluenced by vibration of the printed circuit panel.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described a preferred embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention, but is given for purposes of illustration in order that others skilled in the art may more fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of the particular use.

In the drawings:

FIGURE 1 is a sectional view of an electrical connector assembly according to the invention;

FIGURE 2 is a sectional view similar to FIGURE 1 of an electrical connector assembly showing the printed conductor partially inserted into the channel;

FIGURE 3 is a sectional view similar to FIGURES l and 2 of an electrical connector assembly showing the printed conductor fully inserted into the channel;

FIGURE 4 is an elevational view of a detail of the assembly; and

FIGURE 5 is a graph illustrating the operation of the assembly.

The assembly comprises an elongated insulating housing 1 defining a channel 2 for receiving the edge 3 of a printed circuit panel having thereon printed conductors 4. The housing 1 defines pockets 5 (only two of which are shown) communicating with the channel 2 and each containing a sheet metal contact element 6. Each element 6 comprises a contact spring portion formed as a loop, the bight 7 of which is directed outwardly of the pocket 5, on side of the loop having a rectangularly bent portion 8 engaging one wall 9 of the pocket 5 adjacent the channel 2 and a contact portion 10 protruding into the channel 2, the portion 10 being connected to the bight 7 by an inclined panel guiding portion 11 of the element 6. The other side of the loop has a bowed portion 12 resiliently engaging the opposite wall 9a of the pocket 5 and terminates in a free end 13 on that side of the portion 12 which is remote from the bight 7. The portion 3 is connected by a straight portion 14 to a further rectangularly bent portion 15 engaging a lower wall of the pocket 5 and from which extends through a hole 16 in the housing a tab 17 for connection to an electrical lead, the tab 17 having a struck out lance 18 engaging the lower (as seen in FIGURE 1) wall of the housing 1 to lock the element 6 in the housing in cooperation with the portion 15. The element 6 is longitudinally divided into two equal portions between points a and a on the length of the element 6.

FIGURE 4 shows one of the elements 6 prior to insertion in the housing 1. During the insertion, the portion 12 is cammed towards the portion 14 by an inclined guiding Wall 19 of the housing, so that the element 6 is spring loaded after insertion into the housing, between the wall 9 and the opposite wall 9a of the pocket.

When the panel 3 is initially inserted in the direction of the arrow B into the channel 2, the portions 11 engage the printed conductors 4 thereby causing the looped shaped contact spring portions initially to be deflected away from the walls 9 by a small amount (refer to FIG- URE 2). Each contact spring portion is thus now loaded between the panel and the opposite wall 9a of the pocket 5. The contact pressure exerted by the portions 10 against the conductors 4 accordingly increases rapidly during this initial deflection, e.g. up to 140 grams, During further insertion of the panel and thus further deflection of the contact spring portions, the portions 12 slide downwardly (as seen in FIGURE 3) relative to the walls 9a so that the contact pressure remains substantially constant while the panel 3 is pushed home into the channel 2.

The final contact pressure is accordingly substantially the same regardless of irregularities in the thickness of the panel 3 whilst at the same time the contact pressure is substantially uninfluenced by panel vibration.

As shown by way of example in FIGURE 5, which is a graph of which the ordinate represents the contact pressure expressed in grams and the abscissa the deflect-ion of each contact spring portion expressed in thousandths of an inch (.0254 mm), the contact pressure rises to 140 grams during the initial deflection of the contact spring portion by .006 inch (.1525 mm.) thereafter rising only to 160 grams after final deflection of the contact spring portion by .030 inch (.7350 mm.). In the event one of the two portions into which each contact spring portion is devided is deflected to a greater extent than the other portion due for example to dirt on the panel, the other portion of the spring still maintains eflective contact pressure against the printed conductor, as indicated by lines 0, P, and Q in FIGURE 3 which indicate the contact pressure exerted by the other portion. According to FIG- URE 3, the contact pressure falls only by grams per extra .001 inch (.0245 mm.) of deflection of the one portion. Thus it will be seen from FIGURE 3 that if, for example, the one portion is deflected by .036 inch (9144 mm.) the other portion being deflected only by .032 inch (.8128 mm.) the contact pressure exerted by the other portion drops only by 20 grams.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective against the prior art.

What is claimed is:

1. An electrical connector assembly for connecting an electrical lead to a printed conductor on a printed circuit panel, the assembly comprising an insulating housing defining a channel for receiving an edge of the printed circuit panel, a pocket defined by-the housing and communicating with the channel, an electrical contact element in the pocket, the contact element having a contact spring portion formed as a loop the bight of which is directed outwardly of the channel, one side of the loop engaging one wall of the pocket adjacent the channel and having a contact portion protruding into the channel for making electrical contact with the printed conductor when the panel is inserted into the channel, the contact element having a connecting portion for connection to the lead, the other side of the loop having a bowed portion to resiliently engage the opposite wall of the pocket and terminating in a free end which lies within the pocket and is spaced from the walls thereof, the free end lying=on the side of the bowed portion which is remote from the bight of the loop, the loop being spring-loaded between the one wall of the pocket and the opposite wall of the pocket, wherein upon initial deflection of the loop as a result of a short initial insertion of the panel the loop is spring-loaded between the panel and the opposite wall of the pocket whereby the bowed portion slides relative to the opposite wall upon further insertion of the panel into the channel so that the contact pressure exerted by the contact portion against the printed conductor remains substantially constant and is substantially independent of the extent to which the loop is finally deflected.

2. An electrical connector assembly according to claim 1, wherein the contact element is divided longitudinally into two equal portions, between a point adjacent the free end and a point on the one side of the loop.

3. An electrical connector assembly according to claim 1, wherein one side of the loop has a rectangularly bent portion engaging a shoulder formed by the wall of the pocket.

4. An electrical connector assembly according to claim 1, wherein one side of the loop has an extension projecting from the housing to form a lug for connection to the lead, the lug having a detent engaging the outer surface of the housing, the one side of the loop having a rectangularly bent portion engaging a shoulder formed by the pocket.

5. An electrical connector assembly according to claim 1, wherein sidewalls of the pockets are inclined to facilitate insertion of the electrical contact elements into the pockets.

6. An electrical connector comprising a dielectric housing having a channel therein and a pocket in communication with said channel, an electrical contact member in said pocket and including a spring contact section in said pocket and a conductor-engaging section extending outwardly from one end of said housing, means provided by said housing and said contact member securing said contact member in position in said housing, said spring contact section having a first leg portion and 'a second leg portion, a bight connecting said leg portions together, said first leg portion extending along one wall of said pocket and including a contact-engaging area extending within said channel, said second leg portion extending along another wall of said pocket and having a bowed area for resilient and sliding engagement with said another wall upon said spring contact section being placed under electrical-engaging tension to thereby cause said spring contact section to remain substantially constant and to be substantially independent from the deflection of said bight while being under the electrical-engaging tension, and said second leg portion having a free end lying within said pocket and spaced from the walls thereof.

References Cited UNITED STATES PATENTS 3,120,988 2/1964 Gilbert 3,289,148 11/1966 Antes FOREIGN PATENTS 4/1963 Belgium. 

